Author: M.T. McCulloch
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Yashiyuki Tatsumi
Publisher: Wiley
ISBN: 9780865423619
Category : Science
Languages : en
Pages : 224

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Subduction zones are major sites of volcanism on the Earth. As one crustal plate sinks or is pushed beneath another, hot magma is produced and the resultant magma flux is fundamental to both the thermal evolution and chemical differentiation of the mantle and the Earth itself. To understand these evolutionary processes, we need to understand the physical and chemical consequences of all aspects of the subduction process. In this book, the authors present a simple, current and comprehensive model that explains the dominant geological processes at work in subduction zones. Structuring the book around the model, the authors describe the physical characteristics and geochemical dynamics of subduction zones, arc magma generation, and the dynamics and flow in the mantle. Students and researchers alike will find this book of immense value in understanding this most complex of subjects.

Author: O A Bagatikov
Publisher: CRC Press
ISBN: 9789056991685
Category : Science
Languages : en
Pages : 530

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Magnatism is the only true endogenic process for generating new material on the Earth's surface. Obviously, magmatism and tectonic movements are reflections of geodynamics, that is, physical processes which occur in deep-seated environments. What are the interrelationships between magmatism and tectronics? How did the character of terrestrial magmatism change through time and are there any irregularities in this process?

Author: HARMON/BARREIRO
Publisher: Springer Science & Business Media
ISBN: 1468473352
Category : Science
Languages : en
Pages : 356

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Destructive plate margin magmagenesis is one of the most intensely studied and widely debated topics in the earth sciences at present. Calc-alkaline volcanic and plutonic rocks in orogenic settings exhibit such a diversity of composition and character that the subducted oceanic lithosphere, the overlying 'enriched' lithospheric mantle and the lower continental crust all have been advocated recently as the primary source region for island-arc and continental-margin basaltic to andesitic magmas. The role of the upper continental crust is also a matter of continuing controversy. It is clear that crustal contamination is a common, but not universal, feature of destructive plate margin magmatism. Whether this contamination is introduced at source by subduction-related processes or occurs during magma transit by bulk anatexis and magma mixing, selective contamination or coupled fractional crystallization-assimilation mechanisms is central to most current discussions of andesite petrogenesis. This book presents a series of papers which directly address these and other important geological and geochemical problems within the context of the Mesozoic-Cenozoic calc-alkaline magmatism characteristic of the Andean Cordillera of western South America. Although it is aimed primarily at postgraduate students and researchers familiar with the Andes, it is also a useful general reference for workers in other fields who wish to gain an insight into current thoughts, ideas and speculations on 'andesitic' magmatism at destructive plate margins.

Author: A. Krishna Sinha
Publisher: Geological Society of America
ISBN: 9780813711911
Category : Science
Languages : en
Pages : 892

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The thermal evolution of mountain belts is recorded inthe distribution, origin and ages of magnatism. In this volume, petrologic, isotopic and geochemical evidence is presented to highlight the contribution of igneous rocks to the evolution of the Appalachian Orogen in both Canada and the United States. These papers emphasize the use of modern geochemical and petrologic data to discriminate the sources yielding magmas, and thus the nature of the crust and mantle.

Author: Svenja Rausch
Publisher:
ISBN:
Category :
Languages : en
Pages : 152

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Author: Bernard Bonin
Publisher:
ISBN:
Category : Earth (Planet)
Languages : en
Pages : 380

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Author: Emmanuel Wembenyui
Publisher:
ISBN: 9783838326115
Category :
Languages : en
Pages : 340

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Author: Emma Elizabeth McCully
Publisher:
ISBN:
Category : Geochemistry
Languages : en
Pages : 57

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"Observations of seafloor bathymetry and gravity surveys indicate that magma focuses in the center of slow spreading Mid-Ocean Ridge (MOR) segments, however; it is not well constrained how magma is generated, stored, and transported to the segment ends. There are two end-member models for magma transport: 1) a focused magma model wherein the magma upwells beneath the entire ridge axis, is focused and pools beneath the center of the segment, and is then transported towards the segment ends via lateral diking in the shallow crust and 2) a distributed magma model wherein magma vertically upwells and is erupted on the seafloor along the entire segment, but there is enhanced focusing in the segment center. (Figure 1). Both models are supported by the bathymetric and geophysical observations but have different implications for the chemistry of lavas erupted along the segment. To test how lava chemistries vary along a slow-spreading MOR, we systematically sampled a segment of the Mid-Atlantic Ridge. The segment (~14°N) (Figure 2) is known to host Popping Rocks, gas-rich basalts which, upon reaching surface pressures, explode. Two expeditions to this region in 2016 and 2018 collected both ship-based bathymetry (75 m gridded resolution) aboard the R/V Atlantis and high-resolution bathymetry (1 m) from the Autonomous Underwater Vehicle (AUV) Sentry. 27 dives from the Human Occupied Vehicle (HOV) Alvin collected 382 lavas all of which have been analyzed for major element contents, and 162 have been analyzed for trace element contents. During these expeditions, samples were collected both along and across axis from the magmatically robust segment center, through a transition region, to a sparsely magmatic region. Analytical results show that there is significant chemical variability along this segment. For example, there is less variability at the segment center (K/Ti ratios from 0.24 to 0.46 and La/Sm from 2.58 to 3.59) compared to the sparsely magmatic region (K/Ti values from 0.06 to 0.42 and La/Sm). This suggests that magmas erupted at the segment center are more homogeneous compared to lavas erupting in the sparsely magmatic region. Major element contents in each region vary, but on average, become more mafic moving southward away from the magmatically robust segment center towards the sparsely magmatic region. Petrologic modeling of fractional crystallization and trace element contents show that fractional crystallization dominates the chemical variability in the sparsely magmatic region, while either extent of melting or differing mantle sources dominates the variability in the transitio."--Boise State University ScholarWorks.

Author: Bryan C. Storey
Publisher: Geological Society of America
ISBN:
Category : Science
Languages : en
Pages : 426

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